The Warlock draws his power from strange and terrible forces from beyond the world. Often evil in their own particular way, these are entities who cannot garner followers, and so must bargain for indentured servants to do their bidding. Cruel fiends, capricious fey, deranged elder things, and dead gods need things too.
Here I give some examples of how patrons may approach, co-opt, or otherwise bargain with their warlock servants. I’ll be referring to and utilising Dungeons & Dragons 5e rules, but I’ll leave it suitably ambiguous so that it can readily be adjusted for warlocks, shady spell casters, and dark cultists in any setting or edition.